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802.11 Protocol(WLan Standard)
Introduction:
 Access anytime, anywhere internet.
 IEEE 802.11 is a set of standards for wireless Local Area Networks
(WLANs) computer communication, developed by the IEE LAN/MAN Standards Committee.
 1997 working group approved IEEE 802.11 as the world’s first wireless LAN standard.
 IEEE 802.11 is a subset of IEEE 802 LAN standard.
IEEE 802.11 Protocol:
Covers physical and data page link layer acc. to OSI
 Physical layer:
 Data Link layer
 Spread Spectrum
 Logic Link Control (LLC)
 Media Access Control (MAC)
IEEE 802.11 standards :
IEEE 802.11 standards
 IEEE 802.11 b
 IEEE 802.11 a
 IEEE 802.11 g
 IEEE 802.11 n
IEEE 802.11 b
 Frequency = 2.4 GHz (ISM band)
 Maximum Speed =11 Mbps
 Range = about 38meters(Varies)
 Encoding Scheme = DSSS
 Modulation Technique= BPSK(1 Mbps),
 DQPSK(2 Mbps), CCK(5.5 Mbps,11Mbps)
IEEE 802.11 a
Orthogonal Frequency Division Multiplexing(OFDM)
 OFDM a digital multi-carrier modulation method. A large
number of closely-spaced orthogonal sub-carriers are used to
carry data.
 Although the principles and some of the benefits have
been known since the 1960s, OFDM is popular for
wideband communications today by way of low-cost digital
signal processing components that can efficiently calculate
the FFT.